Soldano Astroverb Clone Speaker Recommendations

[W5FH]

Hello-
For readers who have a few moments I am seeking advice on speaker recommendations for an amp I just finished. It is a copy of the Astroverb preamp feeding into a fixed bias Hiwatt phase inverter driving a pair of 5881's. P/I and power section designed to be as clean as possible. Using a slightly oversized Heyboer output transformer (APD-8025H) and NOS USA Tungsol 5881's. Upgraded the reverb driver and added Sluckey Trem-O-Nator for a really nice vibrato.
The amp is sounding good and guitarist really pleased (pics in amp building section on Hoffman). The upgraded P/I and power section really brings out the tone of Astroverb preamp. It is built on Deluxe Reverb chassis in same 1x12 combo cabinet using a Celestion G12-H-75 speaker. This was the guitarists choice of speaker for a previous build of a clean pedal platform (copy of Fender HRD ML212).
Question #1. The G12-H-75 is really sounding nice in this combo but wanted to ask other Astroverb users for their preferences. I have been reading various message threads and it seems Astroverb users were noticing the speaker choice was more critical to the tone.
Question #2. I am getting a Bassman 2x12 closed-back speaker cabinet built as an option to this amp and to test a future build identical except using pair of 6550's with upgraded power and output transformers. Any speaker recommendations for this? Would only parallel connected speakers be considered, is there ever a reason to series connect two speakers (I am newbie to this).
Thanks all.

[TUBEDUDE]

The speaker is part of your power amp stage.
And as the output stage is considerably different from the original, speaker selections from other Astroverbs are likely not applicable. I'd just plug it into every speaker I had or could borrow. If it also is to be used as a pedal platform, or a clean amp, the usual suspects will be winners. EV, JBL, Weber California, etc.