It seems like the most effective honeymoon suite has a two dwarves, a 2x1 tavern, with burrows that restrict the dwarves from standing on the same square. With some luck from the RNG, friends are usually possible in 7 days, lovers at around a month, and married at six weeks. I'm sure personalities play a role, but I haven't finished testing that yet.
Local time, DF Time(y-m-d), Label, Name(unit#), Stress, RelationUnit=Rank(Attitude)
2019-03-28_21:49:06,5-11-16,NoTag,`WoodWorker' Lizardoiled(83),Stress=-1717,`Miner'Wonderpaint=3(0),
2019-03-28_21:49:06,5-11-16,NoTag,`Miner' Wonderpaint(86),Stress=-4542,`WoodWorker'Lizardoiled=3(0),
..
2019-03-28_21:50:58,5-11-23,NoTag,`WoodWorker' Lizardoiled(83),Stress=-1669,`Miner'Wonderpaint=15(1),
2019-03-28_21:50:58,5-11-23,NoTag,`Miner' Wonderpaint(86),Stress=-4250,`WoodWorker'Lizardoiled=15(1),
..
2019-03-28_21:56:12,5-12-17,NoTag,`WoodWorker' Lizardoiled(83),Stress=-2127,`Miner'Wonderpaint=45(1),`Miner'Wonderpaint=Lover,
2019-03-28_21:56:12,5-12-17,NoTag,`Miner' Wonderpaint(86),Stress=-1629,`WoodWorker'Lizardoiled=45(1),`WoodWorker'Lizardoiled=Lover,
..
2019-03-28_21:59:38,6-01-06,NoTag,`WoodWorker' Lizardoiled(83),Stress=-2970,`Miner'Wonderpaint=50(1),`Miner'Wonderpaint=Spouse,
2019-03-28_21:59:38,6-01-06,NoTag,`Miner' Wonderpaint(86),Stress=-1696,`WoodWorker'Lizardoiled=50(1),`WoodWorker'Lizardoiled=Spouse,