another thing to take in to consideration, where you located ?
I would love to be able to buy the A-51 light but Im in Scandinavia EU and if I order it I have to pay Vat/Tax on +20% wile the Hans panel is sold from Holland I believe so I would not have to pay any tax as its inside EU, dunno how it is the other way around or where you at, just give it a thought
also when you consider shipping time, also if some thing break and you have to use the warranty
the Hans Panel is top quality inside but don't have any secondary lenses, IMOO its a perfect Panel for a small scrog or similar, two Panels could probably flower 2-4 plants in your space depending on size
the Area-51 have them secondary lenses (I have a panel with and with out both different brands tho) and will have double the penetration and cover about the same space as two hans panels
both would be a good choice, I dunno about spectrums, but I do know my Bulldog panel I got customized for flower work great and do have a majority of Red`s (630/660) and some 6500K and a handful of 455, well more easy to show you I guess
and I believe the Red`s to support more dense flowers, but thats just my believe
I know what I would do if it was me, also based on being located in EU
I would get another Hans panel and do a scrog with them two Hans panels in your new space, and then just get a small t5 fixture or a bunch of CFLs and Veg with them, works fine (I use T5HOs) as MJ only need 1/3 of the light in Veg as it need in flowering to thrive and grow and if you like me have 7-9 weeks flowering time you have plenty of time to Veg in, if I start 4 new under my tube`s at the same time I put my 4 Veg plants under the LEDs and 12/12 they easily get "too" big under 4x49W T5HO in them 8 weeks time