Campfire run, combo2:

```
Inference for Stan model: blrm_exnex_model
4 chains: each with iter=(1000,1000,1000,1000); warmup=(0,0,0,0); thin=(1,1,1,1); 4000 iterations saved.
Warmup took (0.085, 0.11, 0.12, 0.080) seconds, 0.39 seconds total
Sampling took (2.0, 1.5, 2.1, 1.9) seconds, 7.6 seconds total
Mean MCSE StdDev 5% 50% 95% N_Eff N_Eff/s R_hat
lp__ -5.1e+01 1.2e-01 5.0e+00 -60 -5.1e+01 -4.4e+01 1.8e+03 2.4e+02 1.0e+00
accept_stat__ 9.0e-01 4.2e-03 1.7e-01 0.55 9.6e-01 1.0e+00 1.6e+03 2.1e+02 1.0e+00
stepsize__ 1.8e-01 1.2e-02 1.7e-02 0.16 1.9e-01 2.0e-01 2.0e+00 2.6e-01 2.0e+13
treedepth__ 4.6e+00 2.2e-01 4.8e-01 4.0 5.0e+00 5.0e+00 4.7e+00 6.2e-01 1.3e+00
n_leapfrog__ 2.7e+01 2.8e+00 6.9e+00 15 3.1e+01 3.1e+01 6.0e+00 7.9e-01 1.2e+00
divergent__ 5.0e-04 nan 2.2e-02 0.00 0.0e+00 0.0e+00 nan nan nan
energy__ 7.7e+01 1.8e-01 7.1e+00 66 7.7e+01 8.9e+01 1.6e+03 2.1e+02 1.0e+00
log_beta_raw[1,1,1] -5.3e-02 1.3e-02 9.8e-01 -1.6 -5.0e-02 1.6e+00 5.6e+03 7.4e+02 1.0e+00
log_beta_raw[1,1,2] 5.6e-02 1.5e-02 9.8e-01 -1.6 6.1e-02 1.7e+00 4.5e+03 5.9e+02 1.0e+00
log_beta_raw[1,2,1] 1.8e-02 1.3e-02 1.0e+00 -1.6 2.0e-02 1.7e+00 5.6e+03 7.4e+02 1.0e+00
log_beta_raw[1,2,2] 2.9e-04 1.3e-02 9.9e-01 -1.6 7.7e-04 1.6e+00 5.4e+03 7.2e+02 1.0e+00
```

Combo2, cmdstan run:

```
Inference for Stan model: blrm_exnex_model
4 chains: each with iter=(1000,1000,1000,1000); warmup=(0,0,0,0); thin=(1,1,1,1); 4000 iterations saved.
Warmup took (2.2, 2.1, 2.1, 2.2) seconds, 8.6 seconds total
Sampling took (2.1, 2.1, 1.8, 2.1) seconds, 8.1 seconds total
Mean MCSE StdDev 5% 50% 95% N_Eff N_Eff/s R_hat
lp__ -5.2e+01 1.4e-01 5.2e+00 -61 -5.2e+01 -4.4e+01 1.4e+03 1.7e+02 1.0e+00
accept_stat__ 9.2e-01 7.1e-03 1.5e-01 0.60 9.7e-01 1.0e+00 4.6e+02 5.7e+01 1.0e+00
stepsize__ 1.5e-01 1.7e-02 2.4e-02 0.12 1.5e-01 1.9e-01 2.0e+00 2.5e-01 3.7e+13
treedepth__ 4.9e+00 1.1e-01 2.9e-01 4.0 5.0e+00 5.0e+00 6.7e+00 8.4e-01 1.2e+00
n_leapfrog__ 3.0e+01 1.2e+00 3.9e+00 15 3.1e+01 3.1e+01 9.8e+00 1.2e+00 1.1e+00
divergent__ 0.0e+00 nan 0.0e+00 0.00 0.0e+00 0.0e+00 nan nan nan
energy__ 7.8e+01 2.0e-01 7.3e+00 67 7.7e+01 9.0e+01 1.3e+03 1.6e+02 1.0e+00
log_beta_raw[1,1,1] -8.1e-02 1.2e-02 9.6e-01 -1.6 -1.0e-01 1.5e+00 6.6e+03 8.2e+02 1.0e+00
log_beta_raw[1,1,2] 9.8e-02 1.2e-02 9.9e-01 -1.5 1.1e-01 1.7e+00 6.6e+03 8.2e+02 1.0e+00
```

combo3, campfire:

```
Inference for Stan model: blrm_exnex_model
4 chains: each with iter=(1000,1000,1000,1000); warmup=(0,0,0,0); thin=(1,1,1,1); 4000 iterations saved.
Warmup took (0.21, 0.22, 0.22, 0.23) seconds, 0.88 seconds total
Sampling took (3.3, 3.3, 3.3, 3.3) seconds, 13 seconds total
Mean MCSE StdDev 5% 50% 95% N_Eff N_Eff/s R_hat
lp__ -7.2e+01 1.8e-01 7.1e+00 -84 -7.1e+01 -6.0e+01 1.6e+03 1.2e+02 1.0e+00
accept_stat__ 9.0e-01 2.4e-03 1.3e-01 0.65 9.5e-01 1.0e+00 2.8e+03 2.2e+02 1.0e+00
stepsize__ 4.4e-01 1.6e-02 2.3e-02 0.40 4.5e-01 4.6e-01 2.0e+00 1.5e-01 1.4e+13
treedepth__ 4.0e+00 nan 1.6e-02 4.0 4.0e+00 4.0e+00 nan nan nan
n_leapfrog__ 1.5e+01 nan 1.6e-01 15 1.5e+01 1.5e+01 nan nan nan
divergent__ 5.0e-04 nan 2.2e-02 0.00 0.0e+00 0.0e+00 nan nan nan
energy__ 1.2e+02 2.7e-01 1.0e+01 105 1.2e+02 1.4e+02 1.4e+03 1.1e+02 1.0e+00
log_beta_raw[1,1,1] -5.1e-02 1.2e-02 1.0e+00 -1.7 -5.8e-02 1.6e+00 6.6e+03 5.0e+02 1.0e+00
log_beta_raw[1,1,2] -8.5e-03 1.5e-02 9.8e-01 -1.6 -5.8e-03 1.6e+00 4.5e+03 3.4e+02 1.0e+00
```

combo3, cmdstan

```
Inference for Stan model: blrm_exnex_model
4 chains: each with iter=(1000,1000,1000,1000); warmup=(0,0,0,0); thin=(1,1,1,1); 4000 iterations saved.
Warmup took (3.8, 3.9, 3.8, 3.8) seconds, 15 seconds total
Sampling took (3.3, 3.3, 3.3, 3.3) seconds, 13 seconds total
Mean MCSE StdDev 5% 50% 95% N_Eff N_Eff/s R_hat
lp__ -7.2e+01 1.8e-01 7.1e+00 -84 -7.2e+01 -6.1e+01 1.6e+03 1.2e+02 1.0e+00
accept_stat__ 9.0e-01 2.5e-03 1.4e-01 0.61 9.5e-01 1.0e+00 3.3e+03 2.5e+02 1.0e+00
stepsize__ 2.4e-01 1.2e-02 1.7e-02 0.21 2.5e-01 2.6e-01 2.0e+00 1.5e-01 1.8e+13
treedepth__ 4.0e+00 nan 5.7e-02 4.0 4.0e+00 4.0e+00 nan nan nan
n_leapfrog__ 1.5e+01 nan 1.3e+00 15 1.5e+01 1.5e+01 nan nan nan
divergent__ 1.3e-03 nan 3.5e-02 0.00 0.0e+00 0.0e+00 nan nan nan
energy__ 1.2e+02 2.6e-01 1.0e+01 106 1.2e+02 1.4e+02 1.5e+03 1.1e+02 1.0e+00
log_beta_raw[1,1,1] -2.8e-02 1.3e-02 9.7e-01 -1.6 -4.6e-02 1.5e+00 5.5e+03 4.1e+02 1.0e+00
log_beta_raw[1,1,2] 1.1e-03 1.3e-02 1.0e+00 -1.7 7.4e-04 1.6e+00 6.1e+03 4.6e+02 1.0e+00
```

Does that help?