Thank you.
The pool base should be level within 1” all around, including the supports for the legs.
If the sand is well compacted you should be ok, I would however have whatever support you use for the legs to be level and flush with the pool base.
That’s a very inviting space you have, I especially like the fire pit.
Long term use of Trichlor tablets, or granular Trichlor/Dichlor chlorine will result in the build up of CYA (stabilizer). As CYA levels rise, so must daily FC levels. As you add more FC through these solid/granular forms, the CYA continues to build. Quickly you will be far past the range of your current test kit, until the required FC level is not economical to maintain.
To avoid this, we recommend using liquid chlorine, aka bleach (sodium hypochlorite). The only other thing added with the FC is a bit of salt. We also recommend your CYA level to be managed independently by using plain CYA.
Yes, the SWG is the way to go, no lugging of bleach bottles, no CYA buildup from solid chlorine, it’s a great convenience. But be aware, it only adds chlorine for you, all other aspects of pool care are the same as a manually dosed pool. In fact, it is best to completely balance your water and maintain a FC level manually with bleach first before adding the SWG.
You should really invest in the proper test kit, if it is available in your location. You need a reliable kit that includes a FAS/DPD chlorine test, pH test, CYA test, TA test, and CH test. We normally recommend the TFtestkits.net TF-100, or the Taylor K2006-C.
Have you read any of the Pool School articles here at TFP?